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Biomedical subjects

B A Wilson

Publications and source records attributed to B A Wilson.

At least 91 records · Page 5Linked to original sources
PubMed1994

The effects of indomethacin on refractoriness following exercise both with and without a bronchoconstrictor response.

Repeated exercise tests demonstrate refractoriness to the development of exercise-induced asthma (EIA). It is unclear whether it is the initial exercise per se or the resulting bronchoconstriction that causes the attenuated response to the second exercise challenge. This study was designed to determine whether the reported blocking of the refractory period by indomethacin requires a significant bronchoconstriction following the primary exercise challenge. Thirteen asthmatic teenagers (aged 12-16 yrs) were tested on four visits. Each visit included two 7 min treadmill exercise challenges at 80% maximum heart rate, separated by a 30 min rest. Conditions for the second exercise challenge (Ch2) were always thermoneutral (20-22 degrees C and 25-35% relative humidity (RH); whilst challenge one (Ch1) was completed twice in thermoneutral and twice in warm-humid breathing conditions (33-35 degrees C and 90-95% RH). A pretreatment for 3 days in a double-blind design with either placebo or indomethacin was completed. Forced expiratory volume in one second (FEV1) was measured before and repeatedly following each challenge. The % fall in FEV1 following Ch1 of the placebo thermoneutral trial was taken as reference. "Percent protection" at each visit was expressed as the decrease in EIA following Ch2, compared to reference. Warm-humid breathing reduced the EIA post Ch1 by 75%, whilst providing similar protection to thermoneutral conditions. Indomethacin had no significant effect on EIA after Ch1, but reduced "percent protection" for both warm-humid (from 67 to 16%) and thermoneutral (from 70 to 26%) conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Spontaneous recovery of impaired memory span: does comprehension recover?

We have previously described a patient, T.B., who had a memory span of two digits and a sentence span of three words. He showed no evidence of effects of either phonological similarity or word length on span and his deficit was interpreted as reflecting the impaired functioning of the phonological loop component of working memory. Analysis of his language comprehension indicated normal processing of short sentences, together with a marked deficit in understanding long sentences, whether these were presented visually or auditorily (Baddeley and Wilson, 1988). When re-tested after several years, T.B.'s memory span had increased to nine digits, and showed clear effects of phonological similarity and word length. His performance on a series of language comprehension tests indicated a complete recovery, although he continued to show impairment on two tests of phonological awareness. These results are consistent with the proposed link between phonological working memory and language comprehension. In addition, they indicate a dissociation between short-term phonological memory and phonological awareness.

Awareness↗
PubMed1993

Partial recovery from visual object agnosia: a 10 year follow-up study.

We describe a young woman, J.R., who sustained a very severe head injury in 1981 at the age of 17 years. She was assessed in 1982 and found to have visual agnosia. Since then J.R. has been assessed on several occasions over a period of ten years. Her agnosia for real objects has resolved and she has improved on the identification of other classes of stimuli. However, she still has some problems with the identification of line drawings, photographs and model animals. Her drawing from memory remains particularly poor and she has difficulty with visual imagery. We consider her residual deficits in the light of Farah's (1990) theoretical framework; this proposes that associative agnosia could be due to a disconnection syndrome, a loss of stored visual representations or to the loss of knowledge of how to perceive objects. J.R.'s residual impairments appear to be mainly due to a loss of access to visual representations in the absence of visual input.

Adult↗
PubMed1993

A case of word deafness with preserved span: implications for the structure and function of short-term memory.

Case IJ shows impaired capacity to repeat individual words despite normal hearing as measured by audiometry and tympanometry. She also has difficulty in identifying other environmental sounds. Her phonological memory span for visually-presented material is normal, and her memory span for spoken digits is only slightly impaired. It is suggested that she has a pre-phonological auditory processing deficit; the implications of this for discussion of the role of phonological short-term memory in language processing are discussed.

Auditory Perceptual Disorders↗
PubMed1993

Adapting the Rivermead Behavioural Memory Test for use with children aged 5 to 10 years.

We describe modifications made to the Rivermead Behavioural Memory Test (RBMT) to make it appropriate for use with children. Results of a sample of 335 children aged 5 to 10 years, attending mainstream schools, are reported. Each child was given two of the four versions of the modified test for children together with a number of tests of memory and achievement from the Wechsler Intelligence Test for Children (Revised WISC-R), and the British Ability Scales (BAS). The children's version of the behavioural memory test (RBMTC) has good interrater and parallel from reliability. The validity of the RBMTC was established in two ways. First, with other tests of memory from the WISC and BAS. Second, a small (n = 36) group of children with severe epilepsy and memory difficulties, attending a residential school, were tested. The houseparents of these children were asked to complete rating scales on everyday memory performance. There was significant agreement between houseparents' observations and scores on the RBMTC (Spearman rank correlation = .71, p < .001), indicating that the test is indeed assessing everyday memory.

Child↗
PubMed1993

A developmental deficit in short-term phonological memory: implications for language and reading.

QU, an eight-year-old boy, was identified from a large scale normative study on the basis of his greatly reduced digit span, combined with normal long-term memory and non-verbal intelligence. Further investigation indicated that his visual STM was normal, but that he was clearly impaired on two verbal STM tests, nonword repetition, and memory span for words. His span showed clear effects of phonological similarity and word-length, suggesting qualitatively normal functioning of the phonological loop component of working memory, despite a quantitative impairment in level of performance. This pattern resembles that found in an earlier study of children with a specific language disorder. We tested QU on measures of vocabulary, syntax, and reading, and found him to be substantially below the age norms on all three. The implications of these findings are discussed for the role of the phonological loop in language development.

Auditory Perception↗
PubMed1993

New activated RAS2 mutations identified in Saccharomyces cerevisiae.

Activating mutations in RAS proto-oncogenes encode proteins with greater GTP binding. Such mutant proteins are responsible for many human cancers. Six new amino acids were discovered that can yield an activated Saccharomyces cerevisiae RAS2 protein when they are altered. These new RAS2 alleles were found among a collection of 35 random mutations that exhibit a dominant reduction of glycogen accumulation. The RAS2-P41S and RAS2-E99K alleles encode proteins that have lost responsiveness to GTPase activating proteins. They affect amino acids in loop 2 and helix 3 respectively and illustrate that GTPase activating proteins recognize a larger portion of the RAS structure than previously realized. RAS2 mutations E130K, S153F, A154T, and A157S alter amino acids proximal to the guanine binding site and probably influence nucleotide binding either directly or indirectly.

Alleles↗